1. Field of the Disclosure
The present disclosure generally relates to computer systems, and more particularly to a computer system providing results of arithmetic operations.
2. Description of the Related Art
A computer processor performs arithmetic operations on different types of numbers, or operands. For example, the simplest operations involve integer operands, which are represented using a “fixed-point” notation. Non-integers are typically represented according to a “floating-point” notation.
Many processors handle floating-point operations within a floating-point unit (FPU). Floating-point processing typically includes addition, multiplication and division operations, may also include other special mathematical operations on a single operand, such as the square root (√{square root over (x)}), reciprocal square root (1/√{square root over (x)}), and reciprocal (1/x) representing functions.
Floating point units (and other arithmetic processors) commonly use multiplier based algorithms for division. These division algorithms initially employ a seed reciprocal of the divisor provided by a lookup table system.
The seed reciprocals have a selected number of bits of accuracy. Iterative multiplies are performed to iteratively increase the accuracy of the reciprocal approximation allowing a final quotient value of predetermined accuracy to be obtained.
The seed reciprocals are typically obtained from a ROM reciprocal look-up table, or equivalent PLA (programmed logic array). The number of table input index bits and table output bits of the seed reciprocals determines the size of the look-up table. More input bits allowing more bits of accuracy in the seed reciprocals reduces the necessary number of iterative multiply cycles, reducing division time, albeit at the cost of exponential growth in the reciprocal table size.
It will be appreciated that a floating point system or method that reduces the needed number of index bits and that reduces or eliminates the need for iterative cycles in resolving operations such as reciprocal, square root, and reciprocal square root would be useful.
The use of the same reference symbols in different drawings indicates similar or identical items.